To identify the underlying genetic cause of autism spectrum disorder (ASD), we performed whole-exome sequencing in 10 unrelated Thai patients with ASD. We identified a novel heterozygous missense variant (c.425C>G, p.Pro142Arg) in the Engrailed 2 (EN2) gene in two patients. The G variant has never been reported in public databases and was absent in 100 Thai patients with ASD and 435 Thai controls. A case-control study showed that the G allele of c.425C>G was significantly associated with ASD (Fisher's exact test, P=0.0359). In addition, the new variant was predicted to be possibly damaging to the EN2 protein by the PolyPhen-2 and FATHMM bioinformatic programs. Our findings suggest that the arginine variant of the EN2 protein may play an important role in the pathology of ASD. Therefore, EN2 protein functional studies should be carried out to determine whether the novel variant has an effect on protein expression.

Suicide attempt is a major public health problem and are associated with genetic factors. This paired case-control study examined the association between the COMT gene rs4680 polymorphism and suicide attempts. A case-control study of 369 (117 men, 31.7%; mean age=44.1±13.3 years) suicide attempters and an equal number of controls without a lifetime history of suicide attempt matched on sex, age, and residence was carried out in rural Shandong, Eastern China. Demographics and psychiatric history were obtained through face-to-face interviews. Blood samples were collected during interviews and the COMT gene rs4680 polymorphism was analyzed using the ligation detection reaction method. The G/G genotype was significantly more prevalent in female suicide attempters than their matched controls. Conditional logistic regression showed that the G/G genotype was significantly associated with an increased risk of suicide attempts only for women (odds ratio=2.3; 95% confidence interval: 1.2-4.2). The findings support an association between the COMT gene rs4680 polymorphism and suicide attempts only in women. Further research with larger samples is needed to explore the interactions of the COMT gene rs4680 polymorphism and sex and psychiatric disorders on suicide attempts.

Reduced social, occupational, and psychological functioning is a hallmark of schizophrenia (SZ). The Global Assessment of Functioning (GAF) score is a measure of the overall psychosocial functioning of an individual on a scale from 1 (lowest) to 100 (highest). In an Icelandic sample, Stefansson et al. (2014) showed that GAF scores were lower in control individuals carrying copy number variants (CNVs) compared to population-based controls with no CNV. To date no study has investigated a possible correlation between GAF scores and CNV burden in patients with SZ. The aim of the present pilot study was to determine the influence of CNV burden on GAF scores in patients with a DSM-IV diagnosis of SZ at several points in time of their life (see below). Patients were recruited in Germany using an existing genome-wide CNV dataset (Priebe et al., 2013). Chromosomal regions prone to false-positive CNV calls e.g. telomeric and centromeric regions; see Levinson et al. (2011) were excluded. The analysis was restricted to “high-quality” CNVs (i.e. those spanning ≥30 SNPs and with a confidence value/log Bayes Factor of ≥30) that overlapped with at least one RefSeq gene. GAF scores (DSM-IV Axis 5) were available for 266 patients (42.1% female) with a mean age [range] of 36.4 years [18–80] recruited from consecutive hospital admissions. To approximate the longitudinal course, we retrospectively collected GAF scores for the following three time-points across the course of the disorder (median [range]): (i) premorbid best functioning (89.5 [58–100]); (ii) “worst ever” (during an illness episode; 25 [5–65]); and (iii) current (at the point in time of remission; 61.5 [30–98]). Wilcoxon nonparametric rank sum tests were used to compare GAF scores in patients carrying ≥1 CNV and patients with no CNV. To determine potential longitudinal CNV effects, the longitudinal nonparametric test (LNPT; R package nparLD, https://cran.r-project.org/web/packages/nparLD) was used. GAF scores were adjusted for age-at-onset/duration of illness and sex by linear regression (Gade et al., 2015). The average number of CNVs per individual [range] was 0.64 [0–4]. Wilcoxon tests showed a trend toward lower psychosocial functioning at the adjusted “worst ever” GAF scores in patients carrying CNVs compared with those who did not (W=9799.5, P=0.112). Median adjusted GAF scores [range] in patients with CNVs were −3.4 [−21.1 to 24.1] compared with −0.6 [−21.1 to 38.0] in patients with no CNV. No effects of overall CNV burden on best, most impaired, and recovery GAF scores were detected by either LNPT or separate analyses of duplications or deletions. Our pilot study provides tentative evidence for a negative effect of CNV burden on psychosocial functioning in SZ patients. The use of high-quality CNVs to avoid false-positive findings may have impeded the detection of true effects. Follow-up analysis of the present pilot results is now warranted in a larger sample and should involve the analysis of smaller CNVs. Acknowledgements We thank the patients for participating in this study. The study was funded by the German Federal Ministry of Education and Research (BMBF) through the Integrated Network IntegraMent (Integrated Understanding of Causes and Mechanisms in Mental Disorders), under the auspices of the e:Med Program. M.M.N. received support from the Alfried Krupp von Bohlen und Halbach-Stiftung and is a member of the Deutsche Forschungsgemeinschaft (DFG)-funded Excellence Cluster ImmunoSensation. M.R. was also supported by the 7th Framework Programme of the European Union (ADAMS project, HEALTH-F4-2009-242257; CRESTAR project, HEALTH-2011-1.1-2) grant 279227. F.D. received support from the BONFOR Programme of the University of Bonn, Germany. T.G.S. received funding from DFG (Klinische Forschergruppe 241: SCHU 1603/5-1), and from the Lisa-Oehler-Foundation. Conflicts of interest There are no conflicts of interest.

Non-syndromic autosomal recessive intellectual disability (ID) is a genetically heterogeneous disorder with more than 50 mutated genes to date. ID is characterized by deficits in memory skills and language development with difficulty in learning, problem solving, and adaptive behaviors, and affects ∼ 1% of the population. For detection of disease-causing mutations in such a heterogeneous disorder, homozygosity mapping together with exome sequencing is a powerful approach, as almost all known genes can be assessed simultaneously in a high-throughput manner. In this study, a hemizygous c.786C>G:p.Ile262Met in the testis specific protein Y-encoded-like 2 (TSPYL2) gene and a homozygous c.11335G>A:p.Asp3779Asn in the low-density lipoprotein receptor-related protein 2 (LRP2) gene were detected after genome-wide genotyping and exome sequencing in a consanguineous Pakistani family with two boys with mild ID. Mutations in the LRP2 gene have previously been reported in patients with Donnai-Barrow and Stickler syndromes. LRP2 has also been associated with a 2q locus for autism (AUTS5). The TSPYL2 variant is not listed in any single-nucleotide polymorphism databases, and the LRP2 variant was absent in 400 ethnically matched healthy control chromosomes, and is not listed in single-nucleotide polymorphism databases as a common polymorphism. The LRP2 mutation identified here is located in one of the low-density lipoprotein-receptor class A domains, which is a cysteine-rich repeat that plays a central role in mammalian cholesterol metabolism, suggesting that alteration of cholesterol processing pathway can contribute to ID.

Genetic research in autism spectrum disorder (ASD) is mainly performed in minors who are legally unable to provide consent. Thus, knowledge of the attitudes, fears, and expectations toward genetic research of the parents is important. Knowledge of the attitudes toward genetic research will improve cooperation between researchers and participants, and help establish confidence in ASD genetic research. The present study aimed to assess these attitudes. Questionnaire-based assessments of attitudes toward genetic research and toward procedures in genetic research of n=1455 parents of individuals with ASD were performed. The main motivation for participation in genetic research is to gain more knowledge of the causes and disease mechanisms of ASD (83.6%), and to contribute toward development of improved treatment in the future (63.7%). The parents also had a positive attitude towards storing genetic information (54.3%) and they requested confidentiality of data (82.9%) and expressed a need to be informed about the purpose (89%) and progress of the research (83.7%). We found a slightly more positive attitude to participation in genetic research among older parents (P=0.015), among fathers compared with mothers (P=0.01), among parents of girls compared with boys (P=0.03), and infantile autism compared with Asperger syndrome (P=0.002). However, linear regression analysis showed that parent and child characteristics seem to have too small an influence on attitudes toward genetic research to be of any relevance (R(2)=0.002-0.02). Parents of children with ASD have, in general, a very positive attitude toward genetic research. Data confidentiality is important, and they express a need for information on the purpose and progress of the research.

Fiorentino, Alessia; Sharp, Sally I.; Kandaswamy, Radhika; Gurling, Hugh M.D.; Bass, Nicholas J.; McQuillin, Andrew Author Information

Liu, Shijinga,b; Maili, Lorenac; Lane, Scott D.d; Schmitz, Joy M.d; Spellicy, Catherine J.a,b; Cunningham, Kathryn A.e; Moeller, F. Gerardf; Nielsen, David A.a,b Author Information

Onodera, Mayuko; Ishitobi, Yoshinobu; Tanaka, Yoshihiro; Aizawa, Sayoko; Masuda, Koji; Inoue, Ayako; Oshita, Harumi; Okamoto, Kana; Kawashima, Chiwa; Nakanishi, Mari; Hirakawa, Hirofumi; Ninomiya, Taiga; Maruyama, Yoshihiro; Kanehisa, Masayuki; Higuma, Haruka; Akiyoshi, Jotaro Author Information

Mandelli, Laura; Carli, Vladimir; Serretti, Alessandro; Sarchiapone, Marco Author Information

Although there is indirect evidence that the effects of antipsychotic drugs may involve modulation of dopamine transmission, their mechanism of action is poorly understood. We hypothesized that antipsychotic drugs mediate their effects by epigenetic modulation. Here, we tested the effect of an antipsychotic, olanzapine, on the DNA methylation status of genes following chronic treatment using rat-specific methylation arrays. Forty-eight hours after the last dose of olanzapine/vehicle, rats were habituated to an open-field activity-monitoring chamber for 30 min to verify whether stress-induced locomotor activity was reduced in olanzapine-treated rats. To test this hypothesis, we examined the effect of olanzapine, a commonly used atypical antipsychotic drug, on the DNA methylation status of 49 genes mapped to human 22q11 and implicated in schizophrenia. Genomic DNA isolated from the cerebellum, hippocampus, and liver of olanzapine-treated (n=2) and control (n=2) rats were analyzed using rat-specific methylation arrays. Significantly reduced locomotor activity of olanzapine-treated rats confirmed the therapeutic efficacy of the drug administered. The effects of olanzapine have been shown through significantly increased (P<0.01) DNA methylation of genes affecting several networks mainly (i) neurological disease, inflammatory disease, and inflammatory response and (ii) cancer, cell death and survival, tumor morphology. Also, proline degradation and L-DOPA degradation were affected by olanzapine-induced DNA methylation. Further, from a set of genes in the 22q11.2 microdeletions that has been implicated previously in psychosis, 29 genes showed increased methylation following olanzapine treatment. The results showed that considerable number of genes (34/49) mapped to human 22q11 and implicated in schizophrenia were affected by olanzapine-induced DNA methylation. The results suggest that DNA methylation may play a role in the therapeutic efficacy of olanzapine.